Anyone running forestry equipment usually knows how important "mud holes" are on track pads. My 30" wide pads usually come through with mud holes already pre-cut but my more often used 24" wide pads come in solid. It takes special order time to get them cut out and lots more cash. I do lots of plasma cutting at my shop so no big deal to make a jig and come up with a solution to speed the cutting process for the 88 track pads that need cutting on a new set of rails. I've been making plasma cutter jig plates for many years now for when I have repetitive cuts. Most jigs are made from easy to work with 1/8" aluminum stock. The trick is to buff the edges where the plasma tip rides along to a smooth edge using a coarse Emory cloth so that the tip sticks minimally during the drag along the side of the aluminum. Keeping the tip and jig slicked off with a wax or vegetable oil also keeps friction to a minimum. An overcut of the jig must account for 1/2 the diameter of the cutting tip where it rubs the side of the jig plate and for the kerf if you need really close cuts. For track pad mud holes, over or under cut is not an issue and neither is perfection of the cut. Just as long as there is an escape hole for debris and it's nearly as large as possible, that's all that matters to this job. When I need a tight fitting jig, like on this one over the bolts, I use the DRO (digital read out) on the vertical mill to make a precision cut jig to snap fit down tight. Another consideration is bringing the work into an easy to reach position to minimize cramping of my muscles and speed up the work. For working on track assemblies, I've used 55 gallon drums but they usually get crushed and wasted from the weight. This time, I made a temporary jig with the forklift and a piece of pipe a little larger than the OD of the sprocket to support the track and get it into an easy to work on elevation. This worked a lot better. Once everything was set, I got all holes cut out of one side (44 units) in about 1.5 hours. Normally, I use cheap cooking vegetable oil spray for anti-spatter and slicking the jigs so they are not as sticky. I tried this DuPont Chain Lube Wax this time with much better results, except when it's still wet and VERY flammable. I've found it at Lowes in the past. Works great for lots of things around the shop. The plasma tip needs frequent cleaning off of the steel slag as the steel is what causes the tip to stick while dragging along the aluminum plate. A pick or file will get off any heavy slag and Emory cloth will get it back down to smooth copper for minima friction. I hope this post helps others. If nothing else, it's a great repository for me to save my notes in. I've made lots of jig plates over the years. Some of the best ones were for cutting out LED lighting holes on the truck frames, chain curtain slotting, notching patterns and other repetitive uses of the plasma cutter.
Have you done anything for bolt holes in pads to install those rubber inserts on mini excavators?
No. I would never consider anything that small for my business. I rent when I need those for personal plumbing work. My Menzi is the smallest excavator that I own.
Was just curious. I have been hearing of customers wanting those rubber pad inserts and they are having some of the companies that build and install thumbs punch the bolt holes in the pads. It seems to me that your jigs with a plasma arc would make that a lot easier and more accurate.
The jigs I build are just a tracing pattern. Not real accurate if the torch head is not 100% perpendicular to the material or the tip slips, consumables get worn and the cutting flame wanders or other things that can happen when working by hand. It all depends on the amount of accuracy required. When I make cut outs for LED lights, there is an acceptable tolerance for a sloppy fit or tight fit with the outer rubber boot. When making chain curtain slots, I have to test fit each hole that is cut due to variances in the cut even though all holes on the jig are machined out identically. My system is not perfect but it is perfect for my needs and saves me lots of time in the long run.
Nice, I make a lot of plas templates. We have a couple we use all the time for foot plates for equipment and pipe stands, we cut them out of all out plate drops.
Important note! Treemuncher is using a Hypertherm with a drag tip. Not all plasma machines are up to Hypertherm's standard.
I make plasma cutter hand templates on my CNC plasma cutter....Made a little sketch showing the cup dia. the kerf size, and how much total offset needed.